A known roof rack includes a pair of roof rails arranged in parallel each other to be fixed on a roof of a vehicle for extending in a longitudinal direction of the vehicle and a plurality of cross rails arranged to be perpendicular to the roof rails for connecting two roof rails for carrying a load. As described, for example, in Japanese Patent Laid-Open Publication No. H10-119657, the position of the cross rail is changeable for carrying the loads with different sizes and configurations with the known roof rack.
Notwithstanding, with the roof rack described in Japanese Patent Laid-Open Publication No. H10-119657, a user tightens screws by rotating an operational knob for fixing the cross rails to the roof rails. With this construction of the roof rack, the fixation is not uniform depending on the users. In case the tightening is loose, the noise due to the vibration is generated during the driving and the loading may be unstable when the heavy load is carried.
A need thus exists for a roof rack including a constant tightening force for fixing a cross rail to a roof rail for securely fixing them.